Embodiments of the present invention are directed to the field of DC-DC conversion circuits.
DC-DC converters such as buck (step-down) converters, boost (step-up) converters, and buck-boost converters, use inductors as a storage element to perform the DC-DC conversion. In addition, DC-DC converter designs also include a current sense resistor for short circuit detection, multi-stage converter load balancing, thermal control, and load independent control. More recently, the inductor DC resistance (DCR) may be used instead of a separate current sense resistor to reduce circuit complexity and reduce losses. However, the DCR value as reported by a data sheet often deviates by +/−15% or more from the actual DCR value of the inductor. In addition, temperature effects can also influence the resistance of the inductor.
The characteristics of the driving waveforms applied to the DC-DC converter for generating various output DC voltages generally depend on the inductance value of the inductor. As such, a DC-DC converter is typically designed to operate in conjunction with an inductor having an inductance within a particular, predetermined range. In addition, the DCR (or the temperature profile of the DCR) of the inductor is generally assumed to be relatively constant over the life of the device.